Boat install

Hey, im plannin on puttin 2 10 inch subs in my boat. Right now they share a box, but its dimensions dont fit anywhere in my boat. I plan to build two boxes and put them under the lid opening type seats in the back, one on each side. I want to know if by doing this the bass will be dampened by the seats and if i will lose sound quality. I would also like help on how to build the boxes if possible. Ill give dimensions if ne1 can help. Thnx,
-Ak
Its a glastron 185 if ne1 knows boats.